Coating compositions



Patented Aug. 27, 1946 COATING COMPOSITIONS -Leonard M. Kebrich andEdwin P. Peterson,

Brooklyn, N. Y., assignors to National Lead Company, New York, N.'Y., acorporation of New Jersey No Drawing. Application July 14, 1943, V

' Serial No. 494,894

Claims.

The present invention relates to paint compositions containing metallicsalts of hydroxy aromatic acids and their derivatives and moreparticularly to paint compositions containing metallic salts of hydroxybenzoic acids, such as lead salicylate.

The principal object of this invention is to offer paint coatings ofimproved durability and Weathering properties, particularly in respectto prolonged film integrity and retarded film breakdown, when exposed tothe weather. Other objects of the invention will become app rent as isnot to be limited either to the lead salicylates Or to the manner ofpreparing such salicylates disclosed in the aforesaid application.

In accordance with the present invention, it has been found that metalsalts of hydroxy aromatic acids in general and particularly metal saltsof alicylic acid confer unusual exterior durability when used to pigmentcommon paint ve hicles, varnishes, paint oils and synthetic resins. Theexceptional durability of these coating compositions manifests vitselfin superior gloss retention, chalking resistance and tint retention. Theuse of a metal salt of a hydroxy aromatic acid in combination with otherpigments also results in coating compositions having much greaterdurability than similar coating compositions which do not contain suchmetal salts. Generally the degree of improvement is proportional to theamount of metal salt used.

For convenience of expression and clarity of understanding, the presentinvention will be particularly described, as regards the use of leadsalicylates as a pigment constituent of paint coating compositions.However, it is to be understood that metal salicylates other than leadsalicylates and metal salts of hydroxy aromatic acids other than thesalicylates also greatly improve the durability of coating compositions,as evidenced by the examples hereinafter set forth showing the use of abasic zinc salicylate and a lead salt of 3-5-diiodohydroxy benzoic acid.The use of zinc salicylate is more particularly described in'ourcopending application, Serial No. 631,790, filed November 29, 1945.Furthermore, representative salts of other organic acids that have beenfound to be of particular. value are 2 those of acetyl salicylic acid,3-5-diiodohydroxy benzoic acid and 2-naphthol, 6-sulfonic acid. It isinteresting also to note that certain halogen-v ated aromatic acids alsoshow considerable improvement in retarding film disintegration when usedina similar manner in paint coating compositions and an example of sucha salt is the. dibasic lead salt of orthochlorobenzoic acid. ffijj Thepreparation of various coating compositions according to the presentinvention is specifically described in the examples presented below. Inall these examples the term basic lead salicylate is intended todesignate the leadjsalt in which the monobasic lead salicylatepredominates. Also presented below will be found various tables Whichclearly show the improved durability and weathering properties of thecoating compositions of the present invention.

EXAMPLE 1 Per cent White lead 71.6 Linseed o 25.6 Drier V .8 Mineralspirits 2.0

The paints of the present invention were prepared with progressivelyincreasing amounts of lead salicylate by replacing the white leadpigment in the control paint formula with an equivalent amount of leadsalicylate. This was done with both normal and the monobasic leadsalicylates, resulting in paints having the following pigmentcompositions: s

number 100% white lead.

99% white lead. 1% normal lead salicylate.

95% white lead, 5% normal lead salicylate.

% white lead, 10% normal lead sal cylate.

No white lead, 100% normal lead salieylate.

99% white lead, 1% basic lead sallcylate.

% white lead, 5% basic lead salicylate.

90% white lead, 10% basic lead 'sal cylate. No white lead, 100% basiclead selicylate.

The above paints were employed as finish coats over a similar, singlepriming coat on duplicate cedar panels exposed at Miami, Florida, on 45southern exposure test fences. Weekly inspections Were made on thepanels and the relative failure graded according to the followingstandards: Pigment A B S:Sught P t P t P z ET CG'IL 67' can 61 087iCCn51derab1e White lead 100 so 50 B=Bad gitanium'barium pigment. 1110 OK6 V Very Magnesium silicate :Less than 100 100 100 The results of thesechalking tests were as follows: 10.-

TABLE I.-CHALKING Exposure in weeks Test paint number a 12 16 2o 24 2832 so 40 1 (control) s B VB VB VVB VVB VVB VVB VVB 2 (s) (s) s o 0 VB VBVB VVB The improved results attained by the practice of the presentinvention are further illustrated in Vehicle A B o the following tablewhich sets forth the period of time during which the respective paintfilms re- 30 Percent Percent Percent malned chalk-free: g 3 a 3 3 TABLEII.-CHALK-FREE TIME 100 m0 100 Time in Increase over Test paint numberweeks white lead 35 I Per cent Composition of paint A B C 1 (control) 62 7 16 P 3 25 317 er cent Per cent Per cent 4 28 367 40 Plgment 72.667.9 67.6 5 40 667 Vehicle 27. 4 32. 1 32. 4 1; 2 8 100. o 100. o 100. 0$1 25 317 9 37 517 45 Six test paints were then prepared according Someof the white lead test paints used in the above Example 1 were alsotested for their durability in gray tints, the test paints being broughtto the same shade of gray by the addition of small amounts of lampblack.They were then painted as finish coats in a manner similar to thosedescribed. in Example 1 and graded in a similar manner to Example 1.Results of these tests were as follows:

TABLE III.-'IIN1' RETENTION (Fading in gray paints) Test paint number 10B VB VB VB VVB VVB S O C O C B S C O B B B EXAMPLE 2 to the presentinvention. Of these six paints, two were similar to control paint A, twoto control paint B and two to control paint C except that in each case apart of the pigment of the respective control paints was replaced withan equal amount of normal lead salicylate or basic lead salicylate togive the followingpigment compositions:

Test paint number figment 10 (control) 100%pigment composition A. V 11pigment composition A, 10% normal lead salicylate. 12 90% pigmentcomposition A, 10% basic lead sell- 0 a e. 13 (control) pigmentcomposition B. r 14 90% pigment composition B, 10% normal leadsalicvlate.

The foregoing paints were employed as finish coats over a similar,single priming coat on duplicate cedar panels exposed at Miami, Florida,in 45 southern exposure test fences. Weekly inspections were made andthe following results were obtained for chalking, the symbols being Ithas also been found that by virtue of the present invention it ispossible to improve the durability of solid color paints pigmentedpredominately with color or black pigments. When such paints, generallycalled trim paints, lose their gloss or challnthey show fading and acorresponding loss of color value. To illustrate this phase of thepresent invention, the following example is presented:

EXAMPLE 3 Typical trim paints were prepared from heat bodied linseed oiland the following colors: Lampblack, Medium Chrome yellow, Prussianblue, Indian red and Toluidine red.

A similar group of paints was prepared from the above colors byextending them with blanc fixe.

For this purpose the colored pigment component was reduced to 60% ofitsoriginal amount and extended with 4 pounds of blanc fixe per gallon. Athird group of paints was prepared in exactly similar fashion exceptthat all the blanc fixe was replaced with an equal volume of normal leadsalicylate. Neither the blame fixe nor the normal lead salicylate in theabove paints appreciably effected the original color tone.

The foregoing trim paints were exposed on vertical panels at Sayville,Long Island for 9 months and then observations were made on glossretention, and resistance to fading. The results of such tests are setforth in TableV below wherein the paints are rated for degree of glossand fading on the basis of a scale, 100 to 0. In this scale 100represents the degree of gloss or the original color exhibited by thepaint before exposure and represents a total loss of gloss or color.

TABLE V.-SOLID CoLoRsCoNnIrION AFTER NINE Mourns EXPOSURE It was furtherfound that the index of refraction of normal lead salicylateapproximates that of linseed oil and that when normal lead salicylate isthe only pigment present in the coating composition, there were obtainedtransparent films similar to those of clear varnishes. Thus, by theaddition of normal lead salicylate, it is possible to improve thedurability of varnishes and clear coatings. In the following exampleheat bodied linseed oil was pigmented with normal lead salicylate andtested for weather durability.

EXAMPLE 4 A heat bodied linseed oil of viscosity Z-2 was successivelypigmented with increasing amounts of normal lead salicylate to give thefollowing compositions (a) 100% heat bodied linseed 011 (b) 89% heatbodied linseed oil, 11% normal lead salicylate (c) 63% heat bodiedlinseed oil, 37% normal lead salicylate After the addition of suitableamounts of volatile thinner and drier these compositions were tested inthe same manner as clear varnishes. Three coats of each of the abovecompositions were respectively applied to similar maple panels exposedat 45 southern exposure at Sayville, New York. After 33 weeks exposurethe condition of the panel was as follows:

(a) Film destroyed, panel blackened, considerable mildew ('b) Goodgloss, film intact, slightmildew (0) High gloss, film intact, no mildewThe above results serve to show the marked improvement in weatherabilitygained by the addition of normal lead salicylate to clear varnishes.

Furthermore, it is evident that, if used in sufficient amounts, leadsalicylate is an effective mildewcide.

The addition of lead salts of salicylic acids also served greatly toimprov the weathering properties of enamels formulated with a syntheticresin vehicle according to the following example:

Other enamels were also made up by substituting, on a volume basis,normal and basic lead salicylate for part of the titanium dioxidepigment of the above formulation, so that there were obtained thefollowing compositions:

19. 100% titanium dioxide (control) 20. titanium dioxide, 20% normallead salicylate 21. 80% titanium dioxide, 20% basic lead salicylateResults of chalking tests on the above pigments, using the same gradingas used in Table I, are given in Table VI below:

TABLE VI.-CHALKING Exposure in weeks Test paint number 19 (control) YBBVB B B B The paints'listed in the above Table VI were tested onduplicate cedar panels exposed at Miami, Florida, on 45 southernexposure fences.

While lead salicylate has been selected as a representative agent fordescribing the present invention, it is to be understood that othermetal salicylates as well as other hydroxy aromatic acids willaccomplish comparable results. The following example will serve toillustrate this Test paints were also prepared in which 13.5% of thewhite lead in the control paint formula was respectively replaced withan equal volume of normal lead salicylate, lead salt of3-5-diiodohydroxy benzoic acid and basic zinc salicylate as follows:

Test paint number Control paint as described above.

13.5% normal lead salicylate substituted for equal volume of white lead.

13.5% lead salt of 35-diiodohydroxy benzoic acid substituted for equalvolume of white lead.

13.5% basic zinc salicylate substituted for equal volume of white lead.

These paints were then painted out on small wood panels and exposed inan accelerated weathering machine (Atlas Weather-O-Meter).

Gloss readings specular) were made on the panels at regular intervals,with the following results:

TABLE Vl'L-GLoss The foregoing description with accompanying examplesand tables clearly discloses a number of embodiments of the presentinvention. However, it will be understood that this invention issusceptible of further various embodiments within the scope of theappended claims.

Having thus described the invention, we claim the following:

1. An improved vegetable drying oil coating composition containing alead salt of a hydroxy aromatic acid.

2. An improved vegetable drying oil coating composition containing alead salt of a hydroxy benzoic acid.

3. An improved vegetable drying oil coating composition containing alead salt of salicylic acid.

4. An improved vegetable drying oil coating composition containing anormal lead salt of salicylic acid.

5. An improved vegetable drying oil coating composition containing abasic lead salt of salicylic acid.

LEONARD M. KEBRICI-I. EDWIN P. PETERSON.

